Additionally, in patients with progressive MS, higher serum GFAP levels were associated with higher EDSS, older age, and longer disease duration (Högel et al., 2020); these findings indicate that astrogliosis may play an increasing role in the advanced stages of the disease and as such serum GFAP may represent a valuable marker of disease progression. The gene discussed is GFAP; the disease is myeloid sarcoma.